Sampling device



March 16, 1965 R. w. STUART ETAI. 3,173,500

SAMPLING DEVICE Filed June 27, 1962 4 Sheets-Sheet l l F.ETJ..

rNvToR @ooe-pr M Srunr BY dDH/v D. Msc-Means March 16, 1965 R. xw. STUART ETAL SAMPLING DEVICE Filed June 27, 1962 4 Sheets-Sheet 2 @P nu March 16, 1965 R. w. STUART ETAL. 3,173,500

SAMPLING DEVICE Filed June 27, 1962 4 sheets-sheet a INVENTORS Poeer h/ 67u99?- Jo/,w D Mss/YBAKER March 16, 1965 R, w. STUART ETAL 3,173,500

SAMPLING DEVICE Filed June 27, 1962 4 Sheets-Sheet 4 United fStan-es Patent @ffice 3,l'13,500 Patented Mar. 16, 1965 3,173,500 SAMPLING DEVICE Robert W. Stuart and-.lohn l). Wisenbaker, Dallas, Tex., 'assignors of one-half to'American Coldset Corporation, Teterhoro, NJ., a corporation of Texas, and one-half to vCore Laboratories,`lnc`., Dallas, Tex. 'Filed June 27, 1962, Ser.'No. 205,644

8.Claims.' (Cl. 175--77)f T hisvrinvention relates generally to a device for obtaining a sample from the Wall ofl a cavity located below ground level, and more particularly to a device for recovering a coresample from the side wall of a drill hole.

In those areas of activity4 which involve explorations below the surface of theearth, there is great needfor a simple, inexpensive method for obtaining true samples of the undergroimdy formations andM recovering portions of their contained iiuids. Such samples are directly useful to aid` in the evaluation of thegeological, mineralogi'cal and physical properties and characteristics of the strata of interest, Such` samples are particularly valuable in activities such as oil well drilling, since they may be analyzed to obtain information relating to the presence or absence of oil content, iluid storage and flow capacities, distribution of contained fluids, fluid liow characteristics, and the ylike of the strata penetrated.

The ever-increasing searchfor new oil and gas deposits in the United States has ledV to the drilling of holesat exceptionally great depths, for example 26,000 feet and more.' The cost of sufliciently extensive coring during the drilling of very deep wells to be certain that no hydrocarbon productive zone is overlooked is excessive in many instances. Also, the likelihood of encountering dicculties during coring in long sections of open or uncased hole is great in some wells. permits recovery of a continuous sample from a preselectedv interval` of drilled hole is of'great value.

'l`l'ie'technologyV of well drilling has advanced. to the stage where the direction of the drill hole can be controlled, and the hole ay be deviated in a predetermined direction if, by so doing, the changes of drilling into an oil or gas reservoir are increased. Samples of the sidewall of the drill hole, where theV directional orientation of the core is established with the sidewall coring tool and the continuous core sample provides information relating to the dip of the strata, are invaluable in determining the directional trend of the strata sampled.

In those instances where a reservoir of oil or gas has been encountered, it, is` necessary to make a preliminary evaluation of the productive capacity in ordertojustify completion of the well. Also, there are many ways of completing wells into these reservoirs to recover the hydrocarbon deposits. For example, the hydrocarbon reservoir may extend hundreds of feet in depth, and one major problem lies in determining the vertical interval or intervals through which the casi-ng should be perforated to provide maximum recovery at desired flow rates. Continuous samples of the prole'ofthe formation are very important to such a determination.

Thepreal merit cfs-corel, or formation sampling is that an actual sample of thel solidformation with theuids contained in itisobtained. Usually, the most important information desired from the samples involves porosity, permeability, water content, and hydrocarbon saturation. Also, direct information relating to fluid iiow characteristics, physical, chemical, electrical and acoustic properties, and the like, are valuableinformation which` can be obtained only from actual samples ofthe formation.

Porosity is a measure of the fluid-carrying orstorage capacity of the formation. Permeability indicates Whether the formation 'fluids will be able to iiow at rates Therefore, an instrument which sufciently fast to. permit economical. production of the hydrocarbon fluid contained. in the formation.

It is most important to obtain the formation sample in the state in which it existed` inV the strata below the surface of the earth. Clearly, some of thedetermina-V tions discussed above, which depend upon the physical structure of the core sample, will be inaccurate if the core sample. itself .is'mishandled, such as by crushing or compaction.

For. many of the studies for which formation samples are utilized, it is very helpful to obtain continuous samples from; a relativelylong distance along the formation profile. In other words, ideally, a formation sample would provide information from which the natural state'ofrscveral feet of a formation proiile couldbe reconstructed.

Eormationsamples obtained` by conventional methods of sampling the wall of a drilled hole heretofore in use were less. than ideal. One of the most widely used sidewallcore sampling methods involves a device which inherently crushes or compacts part of the core sample. Such. deviation4 from` the natural structural state of thesample thus detracts from the accuracy of the information which is obtained by analysis. Likewise, there is not presently available any method of obtaining a substantial continuous length of sample from the walls of a drilled hole whichrwould provide important data about the continuity of the profile of a particular formation.

Accordingly, it is anV object of the present invention to provide an apparatus for obtaining a sample from the wall of a cavity below the surface of the earth which truly reflectsithe conditions prevailing within the formation.

It is another object of this invention to provide an apparatus for obtaining a sample from the side wall of a drill, hole which is truly representative of a substantial length of the formation profile.

It is another` object offthis invention to provide an apparatus which is suitable for cutting and recovering a sample from a formation located below ground level, which, sample is in a state substantially unchanged from that in which it was present n the formation.

It is another object of the invention to provide an apparatus for obtaining a sample from the sidewall ofa dri-ll hole` wherein the orientation and inclinationy ofthe sample are known.

Brieiiy stated, the method. of the present invention for obtaining a sample of the Wall of a'cavity below the surface of the earth comprisesthe steps of making tWo` longitudinal cuts in the Wall, the cuts being co-extensive and in a `rV,configuration.thereby forming a sample in thenshape of a triangular prism, and recovering the said sample.

Oneembodimentof the apparatus of the present invention comprises a housing, cutting means located insaid housing and adapted for making a pair of longitudinally co-extensive. cuts in a V configuration thereby forming a sample in the shape of a triangular prism, and means lo-V cated within said housing for recovering said sample.

Theinventi-on will be more readily understood when described in conjunction with the drawings, in which:

FIGURE 1 is a schematic view depicting the lowering of one embodiment of theapparatus of the present invention into' aV drill hole;

FIGURE 2 is a schematic drawing of the embodiment D assembly of elements including the cutting means and the sample recovery means;

FIGURE 6 is an elevational view partly in section of the portion of the embodiment shown in FIGURE depicting the location of the elements during the cutting operation;

FIGURE 7 is a plan view partly .in section taken along line 7 7 of FIGURE 5;

FIGURE 8 is a plan view partly in section taken along the line 8 8 of FIGURE 6;

FIGURE 9 is a plan view partly in section taken along the line 9 9 of FIGURE 6;

FIGURE 10 is an elevational view partly in section taken along the line 10-111 of FIGURE 5 FIGURE 11 is a perspective view of the cutting means and sample recovery means of the embodiment of FIG- URE 1;

FIGURE 12 is a perspective view of the gear arrangement of a gear box used in the embodiment depicted in the drawings; and

FIGURE 13 is a schematic view of a hydraulic system suitable for operation of the embodiment depicted in the rawmgs.

With respect now to the drawings, and more particularly FIGURE 1, there is depicted one embodiment 10 of the apparatus of the present invention, hereinafter referred to as a sampling device. A housing 11 in the form -of a steel cylinder approximately six inches in diameter and twenty feet long is utilized to contain all of the elements necessary to cut and recover a sample. The cutting means employed in the embodiment depicted involves the use of two cutting wheels 12 and 13 mounted as shown in FIGURE 11, for example. As will be described in detail below, cutting wheels 12 and 13 utilize diamonds or similar cutting elements in order to provide cutting surfaces. Sampling device 10 is lowered into drill hole 14, as shown in FIGURE 1, by means of a cable 15 attached to the upper end of housing 11. When sampling device 10 has reached the desired depth, it is anchored in position by means of shoes 16.

By signals from the ground level, cutting Wheels 12 and 13 are caused to rotate, are moved transversely into engagement with the side wall of the drill hole, and then are moved longitudinally of the wall of the drill hole thereby cutting a sample in the shape of a triangular prism. FIGURE 3 depicts the cutting wheels during the step of cutting the sample.

When the cutting wheels 12 and 13 have reached the end of their longitudinal travel, they are moved transversely out of engagement with the side Wall and into the general position as shown in FIGURE 4. The anchoring shoes 16 are then retracted and device 10 is hoisted to ground level.

As will be described in detail below, a sample recovery means is provided to collect a triangular-shaped sample which is cut from the side wall of the drill hole.

The embodiment depicted in the drawings will now be discussed in detail. It is to be appreciated that the various features and structure of the embodiment may be modified to meet the individual requirements of other applications of this invention.

The embodiment to be discussed concerns the cutting and recovery of a section of the side wall of a drill hole. It is assumed that the drill hole contains a drilling mud of the type conventionally employed in oil well drilling operations. Device 10 is lowered into hole 14 by means of cable 1S which contains a plurality of insulated electrical conductors. The conductors are not shown in the drawings since such a cable is conventional.

When the device 19 is `being lowered in the drill hole, it is necessary that it be properly positioned with respect to the formation which is to be sampled. Such location may be readily accomplished by utilizing conventional well-logging methods. These may be the usual S.P. log or gamma ray log or others which are suitable. Thus for example, S.P. electrodes (not shown) may be connected to the housing 11 and these electrodes may be connected to ground level using the electrical conductors forming part of cable 15. Thus an observer at ground level will receive a continuous log of the formation as the device 10 passes down through the drill hole 14. When the device 10 reaches the desired formation, the cable pay-out is stopped.

The next step is to immovably anchor device 10 within the drill hole 14. For this purpose, a plurality of shoes 16 are provided. In the embodiment shown in the drawings, two shoes are used, one at the bottom and one at the top. However, it is to be appreciated that two shoes could be used at the top, spaced apart at a slight angle, and two shoes could be similarly positioned at the bottom.

In their retracted position, shoes 16 are flush with the outer surface of housing 11. This is shown in FIGURE 1. At a signal from ground level, shoes 16 are forced outward of the housing 11 so that the opposite surfaces of housing 11 are forced against the wall of the drill hole 14.1.

FIGURE 6 depicts one of shoes 16 in detail. In this embodiment, shoe 16 is operated by hydraulic pressure. Plate 17 is fastened to the inside of housing 11. Pins 18 and 19 are fastened to bearing plate 20 of shoe 16. Pins 18 and 19 pass through holes (not shown) in plate 17 and are spring biased by means of compression springs 21 and 22. Piston rod 83 is connected to bearing plate 20 and to piston 23 through a hole in plate 17. Piston 23 is housed in hydraulic cylinder 24. Hydraulic fluid under pressure is supplied to cylinder 24, in a manner discussed below, and thus piston 25 is forced out of cylinder 24. In this manner bearing plate makes contact with the side wall of drill hole 14. This contact, in turn, forces housing 11 against the opposite wall of drill hole 14. Thus, housing 11 becomes anchored or wedged within drill hole 14.

Although the depth at which device 10 is anchored is known, the orientation of device 19 within drill hole 14 and the inclination of device 10 are not known. Orientation here is intended to denote the location of the sample to be cut with respect to true or magnetic north. Since these indicia are very important factors in `the analysis of the samples which are recovered, provision is made for obtaining information relative thereto. There are instruments presently available which embody photographic means, a compass mounted on gimbals, and a means for determining inclination involving the use of a steel ball rolling freely in a curved glass cup. Instruments of this type are available from the Eastman Oil Well Surveying Company and the Sperry-Sun Well Surveying Company and are described more completely in the Eastman Directional Drilling Instrumentation Manual and the Sperry- Sun Well Surverying Instruments and Services Manual, respectively.

Controls for an instrument of the type described above, shown in FIGURE l by reference numeral 919, for determining inclination and orientation are connected to ground level by means of the insulated electric conductors in cable 15. After the device 10 is anchored within the drill hole by means of shoes 16, the instrument described above is actuated, and a photograph or recording is taken which will show the orientation and inclination of the device 10 at the time. The sample which is obtained will ythen be analyzed and the data obtained may be studied in the light of information relating to the sample location within the drill hole.

The next step involves energizing the power means used to rotate cutting blades 12 and 13. Electric motor 25 is the power means used, and it 4is located as shown in FIGURE 1. It is tubular in shape and is suitable for submerged operation. Typically motor is a threephase, 440 volt, 3 horsepower motor which is approximately four inches in diameter and three feet long.

Motor 25 is connected to gear box 27 by means of 5 adapter 39. The design of gear box 27 is shown in FIG.- URE l2. The shaft 26 ofmotor 25 is connected to input shaft 28 of gear box 27. Shaft 28 isconnected to beveled gear 29 which in turn is meshed with beveled gear 30. Gear 3i) is connected to cutting' wheel 12 through shaft 3.4. Also connected to yshaft 34is beveled gear 31 which is meshe'd'with beveled gear 32. Beveled gear 32 is connected to cuttingwheel 13 through shaft 33. Gears 31 and 32 are` of equal diameter and have equal numbers of teeth, and. therefore cutting wheels 12 and 13 rotate at the same speed. The directions of rotation ofthe Variousparts of gear box 27 are shown by the arrows in FIGURE l2'. The r.p.m'. of motor 25 and the gear ratios of gear box 27 arev chosen so that the cutting wheels 12 and` 13l rotate iat approximately 1800 r.p.rn.V

As stated abovelthernotor 25 is energizedv from ground level and't'his in turn causes cutting wheels 12 and '13 to rotate. The next step to cause movement of cutting wheels 12 and 13 into engagement with the. side 'wall of the drill hole 14 and then longitudinally along the side wall thereby cuttinga V-Shaped section.

' As shown in FIGURE l, motor 2 5 is connected to piston rod 3S. Piston rod35 is pivotally connected to piston 36 by means of wrist pin 37'. Piston 36 is* disposed lwithin hydraulic cylinder 3.8. `4Vl/'hfendevice 10 is made ready for use, cylind'er`38 is filled with hydraulic iiuid. Device 10 is provided with a hydraulic system-depicted in FIGURE 13. Suffice it to say at Vthis point, that cylinder 38 is'connect'ed by solenoid operated valves 79 and 3.1 to 'dump chamber 77 Where the hydraulic fluid force from the cylinder 38 may be stored. f i i After motor 25. is energized fromground level, valves 79 and Slin line 'lbetweencylinder 38 and dumpchamber 477 of the hydraulic system are opened. by remote operation. from ground level.Y Since housing 11 is not sealed but has openings therein, the pressure within housing 11 is. equal tothatwithin the drill hole. The pressure within housing 11. is exerted on the exposed face of -pisfoin 35.

As indicated. above, device 1Q is being described in connection with its use in lan oil wellvdrill hole. There is drillingmud in the drill hole. Therefore at the depths usually` encountered in oilwell drilling, the pressurer'in thevicinity of device will be somewherefwithin the range of rive, hundred to ten thousand pounds per square inch. Since electricV motor. 25is connected to pistony 36, andy gear box 27 is connectedfto motor 25 through adapter 39, ythe' entire assembly. moves'in response to the movement of piston` 36.` f

The, manner in which cutting wheels 12- and 13 move transversely into the formation and then longitudinally along theformation, thereby. cutting a triangular-shaped sec-tion, willnow. he analyzed indetail. Shown in FIG- URE 10 is bracket 40 .which is connected to `gear .box 27. Extending outafromthe sides ofbracket 40are bearings 41 andi-l2. Secured to these bearings are guide pins. 43 and 4.4.'

Provided within the housing 11, andl rigidly attached thereto, are guide. bars .45. and 46.` These guide bars 4'5 and.46 are identical inconfiguratio-n andare identically locatedonopposite` sides of-housingll. Guide bar. 46 will be discussed-in detail since it'isfshown inFIGURES 5 and 6. However, it is to benunderstood that the remarks concerningguide. bar` 46y apply equally well to guide bar 45.

Guide'bar 45is provide d witha slot 48. Guide pin 44 rides within slot 4,8. VThis is bes-t shown in FIGURE 7, for example. Also shown in FIGURE 7 is guide.v pin 43 which is located within slot 47 of guidev bar 45. Asr described below, the guide bar and guide'pin assemblies function asa cam and followferto controlthe movement of cutting wheels 12 and 13.

i In FIGURE. 5 cutting wheels 12 and 13are shown in their retracted lower. posit-ion. (See also FIGURE 7.) As seen inV this figure, guide pin 44 is positioned at the lowerniost point of slot 48. With the upward movement of piston` 3.6, within cylinder 38, cutting wheels 12 and 13 move upward. Since guide bars 4.5 and 46 are stationary within housing 11, guide pins 43 and 4 4l ride upward within slots 47 and 48, respectively.

For the iirst short portion of travel, slots 47 and 43 are substantially vertical. Thus during the time that guide pins 43and 44 travel within the vertical portion of slots 47 andV 48, cutting wheels12 and 13 move only in a vertical direction and have no transverse movement. However, when guide pin 44 moves into the inclined. por,- tion 49 of slot 48;, cutting wheels 12 and 13 move both upward ail@ also transversely. In other words, cutting wheels 12 and 13begin to move out of housing 11 and into engagementY with the side Wall of drill hole 14. Since piston 36. moves only in a straight. line within cylinder 38, the horizontal movement of cutting wheels 12 and 13 necessitates the use of wrist pin 37 to pivotally connect piston rod 35 to piston 36.

As shownV in FIGURES, a portion of housing. 11` is cutaway toA provide clearance room for blades 12 and 1 3 to move out of housing 1,1 and into the formation. FIGURE 8 depicts slot 50 which serves this function. It is to be noted that slot 59 affords a direct connection between theinterior portion of housing 11 and the drill hole, and this opening plnsother openings permit equalization of pressure within and without housing 11.

After the short inclined portions, slots 47 and 48 are vertical for a substantial distance. Thus, cutting wheels 12 and 13 move longitudinally ofthe sidewall. FIG- URE 3 shows the cutting Wheels 12 and 13 moving upward through the formation. In the embodiment depicted, the vertical portions of slots 47 and 48 extend for approximately five feet, thereby permitting the cutting of a side wallsample of this length. Itis to be appreciated that the length of sample to be cut by device 10 is a matter of choice, and this may be increased or decreased as. desired.

Slots 47 and 43 have inclined portions at the upper end s, thereby directing the saw blades 12 and 13 out of the formation and bach intothe housing 11. Cutting Wheels 124 and 13 are then located in their upper retracted posit-ion. The retracted position is the same, whether upper or lower. The wheels 12 and 13 are schematically depicted in the upper retracted position in FIGURE 4.

The operation of the devicev 1G .has been described above with reference to the method of cutting the sample out of the side wall of the drill hole 14. It remains to describek how the sample is recovered. Ay sample recovery assembly 875y depicted in FIGURESS. and 6,. is employed for this purpose. It is to be appreciated that the recovery assembly .must follow or track cutting wheels 12- and 13 to insure recovery of the. entire sample. To this end, recovery assembly 85 is. attached to gear, box. 27 asdescribed in detail below.

Lead section 51 of assembly 8.5 ishollow and is triangularV in cross section at its upper end and is circular at its` lower end. Lead section 51 has a bushing 52 connected as shown*v in FIGURES 5 and 10. P-in 53 is secured tombushing 5 2 andthe ends .of pin 53 are engaged in slotsh55` and 56m, respectively, which are located in bracket 4G. Flatuspring 57 is attached atits upper end to gear box 277. It is adapted to engage with bushingA 52 as shown in FIGURES 5 andll).v Thus spring 57. is designed to urge bushing 52in a direction toward the sidewall being sampled. Asvshown in FIGURES 5 and-6, pin 53-is forced against the left hand wall of slot 55 as a result ofthe bias of spring 57. The, circular end of section 51 is connected to upper portion 58 of a telescoping unit. 60 by a pair of compression bands S8 and 89.

Assume the situation as depicted in FIGURE 5 of the drawings in which the cutting blades. 12 and 13` are in their retractedlower position. After motor 25has been energized and piston 35 commences its travel upward Withincylinder 38, the movement of cutting Wheels 12 and 13 is guided by slots 47 and 48 as discussed above. As cutting wheels 12 and 13 move into the formation and then commence their vertical upward travel, spring 57 forces section 51 to move into the kerf formed by blades 12 and 13. The reason that assembly 85 is slidably mo'u'nted to gear box 27 is that at the very beginning of the coring cycle insuiiicient material has been cut out of the formation to clear lead section 51 when it is in its normal position. Therefore, for the first few inches of travel, the formation will push lead section 51 toward the right against the force of spring 57. After the removal of the first portions of formation, lead section 51 will move back to the left under the urging of spring 57. Thus as can be seen in FIGURE 6, spring 57 has now pushed section 51 so that it is in perfect position to intercept the triangular-shaped sample as it is being cut.

With respect now to the telescoping unit 60 assembly 85, as stated above, section 51 is connected to unit 58. Unit 5S is telescopically connected to unit 59. Section 51 and units 58 and 59 are preferably made of heavy gauge metal. As seen in plan view in FIGURE 9, pins 61 and 62 are connected to unit 59. Pins 61 and 62 are engaged in slots 63 and 64 in brackets 65 and 66, respectively.

With reference now to FIGURE 5, unit 60 is depicted at a time when cutting wheels 12 and 13 are in the retracted lower position. In FIGURE 6, at a time when cutting wheels 12 and 13 are moving longitudinally along the side wall of drill hole 14, unit 60 has pivoted around pins 61 and 62 so that it is now substantially vertical. As cutting wheels 12 and 13 move upward, unit 58 slides out of unit 59. Unit 58 is provided with a lip 67 at the bottom thereof which engages collar 68 located at the top of unit 59. The engagement of lip 67 with collar 68 prevents unit 5S from being lifted out of unit 59. As cutting wheels 12 and 13 move upward along the side wall, to the midpoint of travel, units 58 and 59 are extended to their fully opened position. Slots 63 and 64 are provided to permit the entire telescoping unit 60 to move upward as wheels 12 and 13 continue their upward travel.

As stated above, it is very important to recover the sample so that the formation profile can be reconstructed at ground level. It is to be appreciated that the triangularshaped section cut by wheels 12 and 13 does not stay in one piece. It is clear from the shape and location of section 51 that the sample must break off at intervals, and is in fact broken off by section 51. Of course, depending on the characteristics of the formation being sampled, there may not be suficient cohesive strength in the sample being cut and it may break off due to vibration, for eX- ample. Since the total sample recovered may consist of a plurality of pieces, the method of collection must preserve the relationship of the pieces with reference to their respective locations in the formation. In the sample recovery assembly 85 depicted in the drawings, this is i accomplished by collecting the pieces in an apparatus in which the pieces must line up, one on top of the other. In other words, the internal cross-sectional area of assembly 85 is chosen so that a new piece of sample being collected cannot slip past those already collected; the new piece is supported on those pieces already collected. Thus, when the telescoping assembly 60 is fully extended after the cutting operation is finished, the sample pieces are piled up, one on top of the other, within the assembly.

It is this feature of the apparatus of this invention which provides a relatively large sample of a formation prole having substantially the same structural integrity as when the sample was a part of the formation. The importance of this aspect of the invention cannot be overestimated.

It is to be appreciated that three or more sections could be used in telescoping unit 6) if desired. Also a collapsible unit made from metal mesh or canvas is suitable.

FIGURE 7 depicts cutting wheels 12 and 13 in their t3 lower retracted position. 1t can be seen that three cutouts, 86, 69 and 70, are provided to house wheels 12 and 13. Of course, if wheels 12 and 13 were smaller in diameter, these cut-outs would not be needed. However, it is desirable to have as large a sample as possible, and by using wheels of the largest possible diameter, consistent with good design practice, the largest sample cross section is obtained. In the embodiment depicted, the blades are approximately six inches in diameter, substantially equal to the inside diameter of housing 11.

With respect now to cutting wheels 12 and 13, these are best shown in FIGURE 1l. As seen, a plurality of cutting elements, such as diamonds, are embedded on the peripheries 71 and 72 of cutting wheels 12 and 13, and also on narrow rim portions 73 and 74 of both faces of the wheels. In addition, radial Webs 75 and 76 are provided on both faces of the wheels 12 and 13 respectively, and these webs are also faced with cutting elements. The thickness of the peripheral portion of wheels 12 and 13 including the rim is greater than the thickness through the wheels measured from the surface of the web on one side to the surface of the web on the other side. This is to prevent binding of wheels 12 and 13 when cutting longitudinally of the formation.

At the beginning of the cutting process, wheels 12 and 13 move transversely into the side wall of the formation. During this movement, the cutting is being accomplished by the cutting elements embedded in the peripheral and rim portions and also by the elements embedded in the ribs on the outer surfaces of wheels 12 and 13. If there were no cutting elements embedded in the ribs of the outer surfaces of the wheels 12 and 13, the wheels would be unable to move into the formation.

As wheels 12 and 13 move longitudinally along the formation, the cutting is accomplished by the cutting elements on the rim and peripheral portions. As stated above, the thickness of the rim portion of wheels 12 and 13 is greater than the web cross-section. Thus, the kerf made by the rim portions is wider and the cutting elements on the ribs do not encounter the formation.

At the uppermost point of the longitudinal travel, wheels 12 and 13 begin to move transversely out of the formation. During this portion of the cutting operation, the cutting elements embedded on the inside faces of wheels 12 and 13 are uitilized. This is necessary since the wheels must cut their way out of the formation.

Although the embodiment shown in the drawing utilizes cutting wheels as described herein, it is to be appreciated that other forms of cutters may be used. Thus for example, a rod or rods having cutting elements on the end and terminal portions thereof may be employed. Alternatively, instead of the use of two cutting wheels both mounted on the same gear box or motor, individually operable cutting wheels are also suitable. While in the illustrative device shown in the drawings an enclosed tubular housing is provided for supporting the work parts of the device in proper relative positions, it should be emphasized that many other different forms of support assembly may be substituted with equal efficacy.

FIGURE 13 is a schematic drawing of a typical hydraulic system suitable for use with the embodiment described in the above drawings. Depicted in FIGURE 13 are piston 36 and cylinder 38. Also shown is the hydraulic system of the shoes 16 showing pistons 23 and cylinders 24. Dump chamber 77 is connected to cylinder 38 through line 78 and remotely operated solenoid valves 79 and 81. Cylinders 24 are connected to cylinder 38 through lines 80, 82 and 87, remotely operable check valve S4 and remotely operated solenoid valve 81.

At the beginning of the operation, valves 79 and 81 are in the fully closed position. After device 10 has been lowered to the desired level, shoes 16 are activated in the following manner. Valve 81 is opened by signal from ground level. 'The hydrostatic pressure on the lower face of piston 36 exerts a force tending to move piston 36 into cylinder 33. Since valve 81 is open, hydraulic fluid is displaced through check valve Sd, lines 87, 80 and 82 into cylinders 24. The entrance of fluid into cylinders 24 pushes pistons 23 outward. Attache-d to pistons 23 are piston rods 83. The outward movement of piston rods 83 moves bearing plates 20 of shoes 16 into position.

When it is desired to commence cutting operations, remotely operated valve 79 is opened. Piston 36 then moves upward under the urging of the hydrostatic pressure and expels hydraulic fluid through valves '79 and 81 and line '78 into dump chamber 77. During this time, the pressure within cylinders 24 remains equal to the pressure within cylinder 38 and therefore bearing plates 20 of shoes 16 are maintained in their biased position against the side wall of the drill hole. Remotely operable check valves 84 serves to prevent a premature pressure drop within cylinders 24 by a iiow of fluid out of cylinders 2d and back into the system.

When piston 36 reaches the end of its travel, the pressure will be equal throughout the system. Dump charnber '77 is made larger than the capacity of the balance of the hydraulic system, and the pressure therefore will decrease to a relatively low level within the system. At this point, check valve 84 is operated to permit back ow. Compression springs 21 and 22, shown in FGURE 6 in conjunction with shoe 16, will force pistons 23 back into cylinders Z4, and the uid displaced will go through valves 84 and 79 into dump chamber 77. In this manner, housing 1i may be released when piston 36 has reached the end of its travel. Should it become necessary to pull the device out of the hole before the normal termination of the cycle, check valve 84 may be opened, valve 81 closed, and the pressure on shoes 16 released as described above.

The embodiment described above illustrates one apparatus useful in practicing the present invention. The apparatus shown in the drawings is to be considered illustrative of this aspect of the invention. Thus, for example, although the apparatus is described for use in an oil well drill hole, it is to be understood that apparatus of similiar design can be used in any cavity of this nature located below the ground level. Changes in the design and structure of the apparatus described above may be made by one skilled in the art without departing from the spirit and scope of this invention.

What is claimed is:

1. In an apparatus which is to be lowered into a drill hole on a cable and includes a housing and means to receive a sample, means for cutting a sample from the side wall of a drill hole comprising a pair of cutters and means rotatably mounting said cutters Within said housing in a V configuration with the apex directed outwardly of said housing, drive means within said housing to rotate said cutters, and means to move said cutters transversely into the formation beyond said side wall, then longitudinally of said drill hole and then transversely out of said formation, thereby severing from said formation a sample in the general shape of a triangular prism.

2. An apparatus for cutting and recovering a formation sample from the side Wall of a drill hole comprising a support assembly, a pair of cutters rotatably mounted on said support assembly in a V configuration with the apex of said V directed outwardly of said assembly, drive means on said support assembly to rotate said cutters, means to move said cutters lirst transversely into the formation beyond said side wall, then longitudinally of said drill hole and then transversely out of said formation, thereby completely severing from said formation a sample in the general shape of a triangular prism, and collecting means associated with said support assembly for receiving said sample.

3. An apparatus for cutting and recovering a formation sample from the side wall of a drill hole comprising a support assembly having an opening in the wall thereof, a pair of cutters rotatably mounted on said support assembly in a V configuration with the apex of said V directed outwardly of said assembly, drive means on said support assembly to rotate said cutters, means to move said cutters through the opening in said support assembly, first transversely into the formation beyond said side wall, then longitudinally of said drill hole and then transversely out of said formation, thereby completely severing from said formation a sample in the general shape of a triangular prism, and collecting means associated with said support assembly to receive said sample as it is cut.

4. The apparatus of claim 3, in which said cutters are cutting wheels with cutting elements provided in the faces thereof for cutting during the transverse movements of said cutting wheels.

5. The apparatus of claim 3, in which said means to move said cutters includes cam surfaces mounted in said support assembly and cam follower means associated with said cutters.

6. The apparatus of claim 3, in which said collecting means has an input end with an opening therein for receiving said sample as it is cut, and means to move said input end in response to the movements of said cutters to follow generally the path of said cutting wheels.

7. The apparatus of claim 3, which includes means for sensing and indicating the orientation of said support assembly in said drill hole during cutting of said sample.

8. The apparatus of claim 3, in which said support assembly comprises a tubular housing.

References Cited bythe Examiner UNlTED STATES PATENTS 1,705,623 3/29 Mason 175-58 X 1,891,628 12/32 Nichols 175-58 1,919,461 7/33 Burke 175-58 2,327,023 8/43 Banner 175--78 2,546,668 3/41 Kirby 175-78 2,599,405 6/52 Mennecier 175--77 X 2,637,529V 5/53 Howell 175-351 X CHARLES E. OCONNELL, Primary Examiner.

BENIAMIN l, BENDETT, Examiner. 

1. IN AN APPARATUS WHICH IS TO BE LOWERED INTO A DRILL HOLE ON A CABLE AND INCLUDES A HOUSING AND MEANS TO RECEIVE A SAMPLE, MEANS FOR CUTTING A SAMPLE FROM THE SIDE WALL OF A DRILL HOLE COMPRISING A PAIR OF CUTTERS AND MEANS ROTATABLY MOUNTING SAID CUTTERS WITHIN SAID HOUSING IN A V CONFIGURATION WITH THE APEX DIRECTED OUTWARDLY OF SAID HOUSING, DRIVE MEANS WITHIN SAID HOUSING TO ROTATE 